Portable equipment has recently had greater power requirements. These requirements have created a demand for batteries having higher energy density. Silicon is attractive as an active material for a negative electrode for a nonaqueous electrolyte secondary battery because it forms an alloy with lithium and has a high charge and discharge capacity, i.e., 4,100 mAh/g. Japanese Patent Laid-open Publication No. 10-223220 discloses a nonaqueous electrolyte battery using silicon particles as an active material of a negative electrode.